The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 19, 1992
Filed:
Jun. 18, 1991
Tomoyuki Okada, Ottawa, CA;
Naoki Kannen, Utsuomiya, JP;
Tadashi Nishimori, Wakayama, JP;
Rikio Tsushima, Wakayama, JP;
Kao Corporation, Tokyo, JP;
Abstract
A magnetic recording medium which comprises a non-magnetic support and a magnetic layer thereon comprising a binder and powder of a ferromagnetic substance dispersed in the binder, the binder comprising a crosslinked product of a polyurethane having an average molecular weight of 900 to 50,000 and comprising at least one unit of the formula (I): ##STR1## in which R.sub.1, R.sub.2 and R.sub.4 each are an alkylene, R.sub.3 is a hydrocarbon group derived from a di-isocyanate compound and R.sub.5 is hydrogen or methyl, in one molecular thereof and having --OH, --NCO or --OOC--CR.sub.5 .dbd.CH.sub.2 at both terminals of the main chain thereof, provided that the terminals of the main chain are not --NCO when the molecular weight of the polyurethane ranges from 900 to 10,000. The polyurehtane resin can be prepared by using as a starting material a polymerizable dihydorxyl compound of the general formula (II): ##STR2## in which R.sub.1 R.sub.2 and R.sub.4 each are an alkylene, R.sub.3 is a hydrocarbon group and R.sub.5 is --H or --CH.sub.3.